quiddity
Responses from quiddity
| Direct drive/rim drive/idler drive vs. belt drive? Lewm Win correctly described the influence of the Verdier's deliberate use of a trapped layer of lubricant to contribute hydrodynamic drag which lowers the Q of the platter / belt system.That he did not use exactly those terms is neither here nor ... | |
| Direct drive/rim drive/idler drive vs. belt drive? Lewm There is effectively no damping effect available from the two opposed magnets. Eddy currents are proportional to field strength times relative velocity divided by electrical resistivity. The configuration used results in low relative velocit... | |
| Direct drive/rim drive/idler drive vs. belt drive? Hiho When I said "about the lowest creep of any system outside DD" I was thinking that the drive I designed for Thom Mackris was probably slightly lower. I was wrong. I've run the numbers, assuming you are running a 1/2" x 3mil Mylar belt around t... | |
| Direct drive/rim drive/idler drive vs. belt drive? Hiho The creep is proportional to the strain in the belt divided by the parallel sum of the wrap lengths of the pulley and platter.The compliance of the mylar belt is quite low, so there's not much strain present. The wrap length of your "pulley" ... | |
| Direct drive/rim drive/idler drive vs. belt drive? Hiho Consider the speed of three things: firstly the belt on the drive side of the motor pulley, this being the section which is pulling on the platter; secondly the belt on the non-drive side of the pulley, this being the section where the belt ... | |
| Direct drive/rim drive/idler drive vs. belt drive? Sorry that last part was measnt to be for Hiho not Axelwahl. | |
| Direct drive/rim drive/idler drive vs. belt drive? Clarkie You appear to be making two statements: 1: High mass platters improve the speed stability of belt drives2. The transmission in an idler is stiff, so the motor is tightly coupled to the platter.and following them with a conclusion:3. Theref... | |
| Direct drive/rim drive/idler drive vs. belt drive? T-BoneMaybe you have me confused with someone else.I have never advocated the use of any form of slip in a turntable transmission. I understand the theory of it being used in an attempt to reduce cogging but I think it's the kind of half baked ide... | |
| Direct drive/rim drive/idler drive vs. belt drive? Clarkie I can't see where the distinction lies. In both cases you have a passive inertial element (the platter), an active source of energy (the motor, which also has inertia of its own) and a transmission (belt or idler) which links them.The mot... | |
| Direct drive/rim drive/idler drive vs. belt drive? Axelwahl I don't have enough information to make an informed judgement about the SME's controller implementation. Mark Kelly | |
| Direct drive/rim drive/idler drive vs. belt drive? After chiding someone on VA over miunderstanding servo loops I should correct an error in my description of the Denon.Where I said "it also employs a PLL controlled servo loop to slave the coil drive to a motion dependent signal...." I should have... | |
| Direct drive/rim drive/idler drive vs. belt drive? Lew The DP80 uses an iron core stator. The distinction between Denon's "3 phase AC outer rotor motor" and Technics "Brushless DC with integral magnet platter" is largely semantic. The Technics motor is a 3 phase outer rotor motor which includes a ... | |
| Direct drive/rim drive/idler drive vs. belt drive? HiHo Here are a few things which I can prove to be true: 1. Newton's Third Law of motion holds for turntable motors so the reaction torque reflected into the chassis will be the mirror of the forward torque applied to the platter.2. The variation ... | |
| Direct drive/rim drive/idler drive vs. belt drive? Dan It would be giving something away, but you are on the right track. It's the design of the filter that takes all the time and effort in the Spice model. Matt: Q 1 Asked and answered. Q 2 No. Q 3 No. Mark Kelly | |
| Direct drive/rim drive/idler drive vs. belt drive? DanFor the kit designs I had two overriding criteria: they had to be as cheap as possible whilst still providing acceptable performance and they had to be almost universally applicable (hence your comment about platters / bearings). Unfortunately ... |